Enhancement of concurrent yield of spermatogonial, meiotic I, and meiotic II metaphase chromosomes from Chinese hamster testes.

A procedure to enhance the concurrent yield of large numbers of spermatogonial, meiotic I, and meiotic II metaphases from Chinese hamster testes has been developed. Animals were injected intraperitoneally with 5, 10, 20, or 40 mg of colchicine/kg and killed 3 hr after the treatment. Both testes from each animal were excised; one testis was minced, and germ cells were isolated by using 0.1% trypsin solution; the other testis was minced, and germ cells were isolated by using a conventional procedure. Chromosomal preparations were made with a standard air-drying technique. Examination of slides revealed that with the trypsin-isolation procedure the concurrent yields of spermatogonial, meiotic I, and meiotic II metaphases were significantly higher (P less than .05) than the yields obtained with the conventional procedure. Furthermore, 40 mg of colchicine/kg produced maximum numbers of all three types of germ cell metaphases. At this maximum concentration, metaphases were stable with no evidence of structural aberrations, and the frequency of hyperploidy was not significantly different (P greater than .05) from hypoploidy.